Process of making sulfuric acid.



H. HOWARD. PROCESS OF MAKING SULEURIC ACID.-

APPLIQATION FlLEDjUNEZB, I914.

HENRY HOWAR or BaooKLmE, MASSACHUSETTS.

PROCESS "or MAKING SULFURIC ACID.

Specification of Letters Patent.

Patented Auger, 1915.

Application filed June as, 1914, Serial N 347,498.

To a /10/12 it may concern Be it known that I, HENRY HOWARD, a

citizen ofythe United States, residing at- 'Brooklin e, in the county of Norfolk and State of Massachusetts, have invented certain new and useful Improvements in Processes of Making Sulfuric Acid, of which the following is a specification. a

This invention relates to processes of making sulfuric acid by the oxidation of sulfur dioxid by nitric acid, as for example in the chamber process.

The object ofthe invention is to provide -a process .according to which nitric acid, or

a mixture thereof with oXids of nitrogen available for the oxidation of sulfur dioXid, may be introduced -in regulated, uniform and continuou flow into the stream of gases cl'arrying'sulfur dioXid, while at the same time sodium sulfate (Na. ,SO,) is produced as-a 'by-product. The gaseous reaction products, including the nitric acid, are hereinafter referred to as the evolved oXids of nitrogen.

It is customary to evolve nitric acid from a mixture of sodium nitrate and sulfuric acid introducedat intervals into the niter pot, located in the burner-gas flue. This method yields as a residue the comparatively valueless acid sulfate of sodium (HNaSOQ and presents the disadvantages of affording an intermittent or at best ununiform supply of-nitric acid and of involving some dilution of-the burner gases by air When the pots are charged or discharged. It has been sought to overcome these difficulties by the direct introduction of nitric acid in a regulated stream, usually to the Glover tower; but this method hasproven so expensive as to Zprevent its general adoption.

ccording to the present prdcess, sodium nitrate and sulfuric acid are intimately mixed in the proportion of two molecules of sodium nitrate to one molecule of sulfuric mingled with the burner gases, or. with the sulfur dioxid at any desired point in its a movement to the chambers; and, on theother hand, 'to prepare directly a marketable grade of sodium'sulfate.

While the nitric acid producedaccording to the present process is accompanied by a certain proportion of other oxids of nitrogen, this is not, under the conditions, amaterial defectinasmuch as all of the higher oxids of nitrogen are in any case immediately reduced upon contact with the sulfur dioxid.

A preferred form ofapparatus for carrying out the present invention is illustrated in the accompanying draw1ng,.where1n the figure 1s a vertical sectional v1ew.

In said figure, 1 represents a covered mix action in the vessel 1, passes by the outlet to a screw conveyer 5, and is delivered continuously and uniformly to the mechanical.

furnace 6; This furnace is provided with a rotary stirrer 7, driven by a shaft vS, entering the furnace through a stufling-box 9 in the cover. i

' 10 is a scraper for keeping the stirrer free from accumulations. I

In the construction illustrated, the mechanical furnace 6 is mounted in the bu nergas flue l1, and receives its heat froni the hot gases. The evolved oxids of nitrogen flow through'the openinglZ and thence, as indicated by the arrows, to the burner-gas flue 11, thecombinedgases'then passing to the Glover tower through the flue/13. Or, if desired, the nitric gases maybe introduced into the current of sulfur dioxid in the Glover tower, or at any suitable point in its movement to the chambers. The sodium sulfate which constitutes the solid residue of the reaction, is kept in loose, solid condition by the vigorous stirring and is continuously discharged by the stirrer 7 through the outlet 12, and collects at 145- whence it may be recovered as desired.

By proceeding as above described and properly regulating the speed of the conveyer 5, I am enabled to provide a continu- -ous and unifort -'-'olut1on of OXlClS of n1tro- 609123 of this'patent may be obtained for gen5' in quantity accurately adjusted to the requirements of the process, Without diluting the burner gases by air. I am, moreover, as-above stated, enabled to obtain as a by-product, marketable sodium sulfate in place of the acid sodium sulfate which is the residue from the ordinary niter pots.

1} In aprocess Ofmaking sulfuric acid, the steps which consist in continuously feeding sodium nitrate and sulfuric acid to a suitable reaction. vessel in substantially theQproportion of tWo molecules of sodium nitrate to one molecule of sulfuric acid, heating the sald mixture, stlrring the reactlng mass, commlngllng the evolved 0X1ds of .nitrogen with the gases containing sulfur dioxid, and continuously discharging the residual solid sodium sulfate.

five cents each, by addressing Washington, C.

2. In a process of making sulfuric acid, the stops Whichconsist in continuously feeding an intimate mixture of sodium nitrate and sulfuric acid to a. suitable reaction vessel' in substantially the proportion of two molecules of sodium nitrate to one'moleculo of sulfuric acio heating the said vessel, stirring the reacting mass, commingling the evolved oxids of nitrogen with the gases containing sulfur dioxid, and continuously discharging the residual solid sodium sulfate.

In testimony whereof I aflix my signature in presence of two Witnesses.

HENRY HOWARD.

Witnesses: M. V. OBRIEN,

EVERETT E. BRAINARD.

the Commissioner of Patents, 

